Electromagnetic control for injectors of internal-combustion engines



8- 1944- o. FUSCALDO 2,356,577

ELECTRO-MAGNETIC CONTROL FOR INJECTORS OF INTERNAL COMBUSTION ENGINES Filed Jan. 30, 1941 INVENTOR I ATTORN EYS Patented Aug. 22, 1944 TORS OF INTERNAL-COMBUSTION GINES Ottavio Fuscaldo, Milan, Italy; vested in the Alien Property Custodian Application January 30, 1941, Serial No. 376,678

; In Italy February 12, 1940 2 Claims.

The present invention consists of improvements in the electromagnetic control of injectors for internal combustion engines, and the main obiect is to improve certain parts of the injector: operating means including those which are particularly subjected to friction and percussion.

In the specification of copending application Serial No. 305,419, filed November 21, 1939, now Patent No; 2,297,399, issued September 29, 1942', the necessity was explained for having the friction and percussion surfaces very hard, and for this p p se the plan was indicated of hardening the percussion surfaces of the armature or core parts by means of chrome treatment after rolling. Such hardening has been found tobe insufllcient in practice particularly for injectors operating at very high frequency since the iron under the chromium pulls and the chronium peels off.

This invention presents an advantageous plan, which is disclosed by an example, and which will be clearly understood from the following specification. referring to the annexed drawing wherein the single figure represents, with details, the portion of the injector at and surrounding the parts of the armature.

The general parts include the fixed armature or core part 4, partly annular, and the aligned movable core 5, normally slightly separated, with a small magnetic gap A between them. A 'nonmagnetic or bronze tube or spool l2 surroundsthe core parts and this carries the solenoid coil 30, confined by end flanges. the left flange 2 also const tuting a guide for the movable core part I. Said part I is connected by an open web with a non-magnetic or bronze hub .8 fast on an axial rod 8, which may be the injection valve stem, immersed in the liquid fuel, as more fully shown in the conending application. An interior helical spring I i is shown pressing leftward on hub 8 to open the gap A and close the valve, but adapted to be overcome when energization of coil Ill creates magnetic pull to close the gap and open the valve.

In accordance with the present improvement, the pe cuss on surfaces are not those of the soft iron armature parts I and 4, but are supplemental axial hardened steel impact parts 36 and 34. the

first projecting from the hub 8 and being preferably an integral part of the stem or rod 9. whereas the second is an elongated stud fixed within the hollow core 4 as by removable mounting in a hollow bronze plug 25 seated in the core 4. This arrangement is also convenient for holding the tapered helical spring ll, which surrounds the impact parts and it and is seated on in 25 and-hub 8. g

The dimensions are such that the play or magnetic clearance A between the free armature B and the fixed armature I is more than the mechanical play or gap B between the impact pieces 34 and 36, to the extent of a few hundredth parts of a millimeter, so that when the valve is open and parts 34 and 36 touch each other, the parts 5 and 4 are very close together but without touching, of advantage when the spring again asserts itself.

The steel stud member 34 may be fixed to the non-magnetic plug 25 by forcing and soft welding, but in such manner that it is magnetically insulated from the material of core 4. The steel impact member 36 is magnetically insulated from the iron of core 5 as already described. The details of an embodiment of the invention can be varied without departing from the essence of the invention.

What is claimed is: Y

1. In an electromagnetic actuating means for an internal combustion engine injection valve having a valve stem, comprising longitudinally fixed and movable iron core parts providing a magnetically-closing and spring-opening gap; the combination of a co-actingpair of axial impact pieces of steel carried respectively by the fixed and movable core parts, the impact piece carried by the fixed core part being magnetically insulated therefrom and mounted in such location that the magnetic gap between the two core parts exceeds minutely the mechanical clearance,between the two impact pieces, whereby when the impact pieces are in contact, the two core parts are held minutely close together but without substantial contact; so that impact between the iron core parts is prevented.

2. In an electromagnetic actuating means for an internal combustion engine injection valve, the combination of an annular fixed core member, a sleeve of non-magnetic material axially mounted therein, an impact member of hardened material mounted in said sleeve and extending into proximity to one extremity of the fixed core member, an annular movable core member arranged for movement axially of the fixed core member, a hardened metal impact member mounted centrally of the movable core member and extending beyond one extremity thereof into position to contact said impact member of the fixed core member wh le sa d fixed and movable core members are minutely spaced from each other, and a coil spring encircling said fixed impact member and extending beyond the free extremity thereof when the actuating means is deenergized into position to engage the movable core member as it approaches the fixed core member when the actuating means becomes energized to thereby cushion the impact between said impact members and compress the spring into position to force sepa ration of the core members when the actuat- 1 8 means is again deenergized.

OTTAVIO FUSCALDO. 

